Control Box

More etching, drilling, and soldering this weekend… this time it was the main control board. I was much more confident in my techniques this time around, and it definitely made the effort less painful and the results came out better than last time. I am still not sold on the toner transfer method for the artwork, but for an el-cheapo solution it definitely gets the job done. I had a tough time getting the toner to evenly seperate from the paper around the board border, which indicates I was focusing my pressure and time towards the middle (true) instead of evenly across the entire surface. It turned out OK for the most part (as good as I should expect for 1 sheet from a $4 box of paper), and thank god it wasn’t for the trace etching – that turned out flawless since I used the exposure method for them.

I got the control board mounted into the box and connected up all the cables… when powered on, the hardware all mostly behaved as expected and designed – the software, however… not so much. Something in my design makes the “pump on” LEDs significantly dimmer than expected – maybe from running it through the CMOS 4001 quad nor gates… I don’t know. Its annoying, but not catastrophic.

I have a couple of vicious ghosts in the machine to exorcise before its ready for use… meaning code bugs. About 95% of the problems I found today were software related, not hardware or cabling. I am not entirely suprised given that I re-coded the BASIC off-the-cuff during lunch a few days ago, and did not have a PICAXE 28X1 handy to test it on. It all looked like it SHOULD work, but I missed a few important things when I was coding. I expect to be able to straighten them out sometime this week. I suspect a couple runs through the simulator could have caught this stuff…

Some of the big “To Dos” remaining are:

to build the skid that the box and pumps go on (but Donna’s had rotten luck with schedule and weather as far as welding goes…)

Drill a hole in a 1/2″ stainless fitting and weld in some 1/4″ tubing as a thermowell

Put the enclosure “door” on … hinges are already purchased, its just a matter of doing it. Not sure how I am going to lock it closed though….

yeah, pretty much all of the weld-on is gone. it all evaporated, despite keeping it in the beer fridge downstairs – that stuff is volatile!

As for closing the access side – yep. I’ve got that in the works as we speak. All it needs is a little time to set (I put in a couple extra pieces of acrylic / plexi), some minor drilling and gluing, and we’re all done. I’ll definitely post pictures once it is complete.

Do you already have the stuff you need to make a stir plate? I need to get by Radio Shack for some rare earth magnets, a potentiometer, and some other stufff….

Well, I am not electrician, but I definetely have some stuff. I have the 12V fan that I told you about, a “used” wall dimmer switch, and a small sampling of rare earth magnets from a sample pack, they’re not very big, but we’ll see.

Since the fan can be plugged directly into the wall, I was figuring there is a way to wire it onto a dimmer switch (I think via your suggestion) and use the dimmer as the speed regulator.